Why Homebrew fermentation take weeks

[steve1969]

How can companies make beer in few days??
Where as my beers always takes weeks until I bottle them!
Is it all down to the yeast and temperature?

 

[Slid]

There are many reasons - large batches have better temperature control - brewing with a large colony of wet yeast cuts 1 or 2 days out - use of fining or filtration to aid clearing might cur out a week - commercial beers are often a bit green - great advertising and presentation compensates for poor quality - and many more.

Commercial brewing is basically about speed - producing as much product from the brewery as possible to have something to sell.

Have a flick through something like the attached, if you feel inclined to get a feel for the brewing process

http://www.howtobrew.com/section1/chapter1.html

 

[BenM41]

temperature is the big thing. if you keep a fermenter in a water bath (aka controlled temp), the yeast will be closer to optimum conditions for reproduction and respiration - and therefore producing more alcohol at a quicker rate. because of the higher temps achieved in a brewery vat, the density of oxygen in the liquid will be lower too, thus aiding anaerobic respiration - the less oxygen, the better!

but yeah, as mentioned previously, we leave our brews to condition (clearing, adding flavours); where as breweries filter it and/or use finings to make it drop in a much shorter time. without the added bonus of flavours of course (which come from the esters, aldehydes and ketones upon small amounts of slow oxidation).